The tracks used in the analyses have to fulfil a set of selection criteria to ensure high tracking efficiency and d\(E\) /d\(x\)  resolution. Each track was required to have at least 70 of up to 159 clusters in the TPC attached to it, with the (rather loose) requirement, that the \(\chi ^2\)  of the momentum fit is smaller than 5 per cluster. Tracks with kinks due to weak decays of kaons and pions are rejected. To achieve final precision the accepted tracks are refit while the track finding algorithm is run inwards, outwards and inwards again (for more details on the ALICE tracking see [1]} and section 5 of [2]}).
